#include "apue.h"
#include <errno.h>
#include <limits.h>

#ifdef OPEN_MAX
static long openmax = OPEN_MAX;
#else
static long openmax = 0;
#endif

/*
 * If OPEN_MAX is indeterminate, this might be inadequate.
 */
#define OPEN_MAX_GUESS 256
#endif

long
open_max(void)
{
    if (openmax == 0) {   /* first time throught */
        errno = 0;
        if ((openmax = sysconf(_SC_OPEN_MAX)) < 0) {
            if (errno == 0)
                openmax = OPEN_MAX_GUESS;   /* it's indeterminate */
            else
                err_sys("sysconf error for _SC_OPEN_MAX");
        }
    }
    return(openmax);
}
